1. Field of the Invention
This invention relates to an apparatus and a method for folding a flat cable.
2. Description of the Related Art
In general, as disclosed by, for example, Japanese Patent Public Disclosure No. HEI 10-321063 (1998), a flat cable is a sheet-like wiring body comprising a conductive core for constituting a given circuitry and an insulation resin sheath covering the conductive core. Such flat cable is utilized as, for example, a roof harness to be arranged in a vehicle roof. The roof harness may become as large as, for example, 3000 mm in length and 1500 mm in width when the harness is developed on a drawing board. Upon producing the roof harness, a trunk line part and branch line parts are produced individually and then are assembled at the final step.
A process of producing the branch line parts includes the steps of coupling a connector to an end of a strip-like flat cable, folding a flat cable at suitable positions in accordance with a final arrangement pattern having bent paths, attaching external parts such as a clamp to the flat cable, and electrically connecting the branch line parts to the flat cable constituting a trunk line part.
In the step of folding the flat cable constituting the branch line part, an operator marks folding lines at predetermined folding positions on the flat cable and folds the flat cable along the marked lines on the flat cable on a work table such as a drawing board.
It is required to precisely maintain at least a folding angle and to enhance the efficiency of the many folding steps in a folding process of the flat cable described above.
However, in the case where the folding work is done manually in accordance with only marking lines for folding the flat cable, it will become difficult to accurately make creases on the marking lines, thereby lowering not only the accuracy of the dimensions, but also operability.
Such folding steps includes an operation of successively folding the flat cable at two adjacent positions on the flat cable. In the case of carrying out a successive folding operation, the operator folds the flat cable at a first working position in accordance with a first marking and then folds the flat cable at a second working position in accordance with a second marking.
However, in the case of manually carrying out successive folding in accordance with the markings, since it was difficult to precisely fold the flat cable at the first working position and it was necessary to fold the flat cable at the second working position near the first working position, it was more difficult to precisely fold the flat cable at the second working position in accordance with the second marking. Consequently, accuracies in dimension and working in successive folding operations will be lowered.
A crease of the flat cable formed at the first working position is unstable in position on account of a recovery force of the flat cable. Consequently, when the flat cable is folded at the second working position, the worker must make a second crease in the flat cable at the second working position while maintaining the first crease in the flat cable at the first working position. This will lower the efficiency of operation.
In the step of folding the flat cable constituting the branch line part, an operator marks folding lines at predetermined folding positions on the flat cable and folds the flat cable along the marked lines on the flat cable on a work table such as a drawing board.